【作者】 宋芳芳；

【导师】 孙小菡； 张国兴；

【作者基本信息】 东南大学 ， 物理电子学， 2005， 硕士

【摘要】 行波管(TWT)宽频带、高增益、长寿命和高可靠性的特点,使其成为通讯系统、雷达、电子对抗、地面站、微波加热等系统的核心器件,在现代化高科技战争中担负着极其重要的作用。在TWT的各种特性中,热特性是一项非常重要的指标,是决定TWT平均输出功率的主要因素,同时还直接影响着TWT工作的稳定性和可靠性。随着TWT研制技术的发展,其热可靠性问题已经越来越引起人们的关注。在影响TWT可靠性和热特性的各类因素中,电子枪阴极组件最易引起整管失效,成为制约其可靠性保证的主要来源。阴极内部的热量分布、热损耗等问题已受到制管厂家的极大重视。本文依据国内制管单位的需求,重点进行TWT阴极组件热状态分析以及优化设计的研究,分析电子枪内部热量传递过程,为实现国产TWT整管可靠性设计奠定基础。论文基于ANSYS有限元法(FEM)软件进行了电子枪阴极组件瞬态热模拟分析,并将数值模拟、试验和理论分析结果进行比较。从接触热阻的角度分析了数值模拟和试验结果的差异,证明有限元热模拟方法可信且符合实际。在此基础上,确定了热优化设计的控制要点,提出了三种优化方法,开展了模拟计算。选取制管单位最容易改进的一种优化方法进行了制样和实验。结果证明经过优化设计后的电子枪阴极,能够有效地缩短阴极启动时间。同时,在WINDOWS平台上开发出基于ANSYS的TWT电子枪热分析应用程序,便于TWT设计人员进行电子枪阴极的分析和设计。本论文系统建立了电子枪阴极组件热模拟FEM分析模型和热优化设计平台,获得典型电子枪热阴极的温度分布、热流分布及预热时间等参数,在给定加热功率下优化阴极工作温度,缩短阴极预热时间,提高了行波管快速反应能力。为快热型TWT阴极组件的优化设计研究奠定了基础,也为整管热可靠性的评价提供理论和数值仿真依据。更多还原

【Abstract】 With the characteristics of wide band, wide pulse, long life and high reliability, TWT is the key device in electronic communication systems, radar, electron counter measurement, ground workstation and microwave heating. It takes the important function in modern high-tech battle. Thermal character is one of TWT’s very important guide-line in all kinds of its characters, which is not only the main factor to decide the average power output, but also directly affects TWT’s work stability and reliability. With the development of manufacture technology, its thermal reliability problem has attracted more and more people’s attention.Among the factors affecting TWT’s reliability and thermal performance, cathode module is the easiest part to fail, and then becomes the main source providing TWT’s reliability guarantee. The thermal distributing,thermal dissipation inside electron gun has attracted the attention of production units, for example the thermal dissipation greatly delay the warm-up time of cathode. According to the requirements from TWT industry in China, this paper focus on analyzing the thermal status and optimal design of cathode module in order to built up the background for reliability design of TWT in China.Thermal dissipation of cathode module is simulated and analyzed with the FEM application-ANSYS in this paper, especially cathode module that is the uppermost part for thermal dissipation in electron gun. Comparing simulation results with test results and mathematic calculation, and explaining the differences by thermal contact resistance, the FEM thermal simulation technology can be proved to be correct and credible. Controlling points and methods to optimize cathode module are confirmed based on above results, and then three of optimized methods are provided for the selection. The easiest method is chosen to prepare sample for experiment about an M-type cathode. Simulating results prove that the optimized thermal cathode module can effectively shorten the warm-up time of cathode. An appropriative analysis system with VB7.0 edits environment on the WINDOWS platform has been developed, which is convenient for the TWT’s designer to analyze and fabricate the TWT cathode module.Thermal FEM simulation and optimal designing platform for cathode module in electron gun of TWT has been set up. The thermal distribution chart, heat flux chart and warm-up time have been obtained so that optimize the key structure, material and technology in order to improve cathode work temperature, shorten the warm-up time of cathode under the given heat power. These results will supply the theory basis for fast warm-up cathodes, and provide theory and emulation technology basis for studying the thermal character of full TWT electron gun.更多还原